Various attempts have been made to reduce power consumption of a personal computer. For example, in Patent Document 1, a micro computer system is disclosed by which it is possible to control a power supply to a main CPU portion in a more appropriate manner and reduce the power consumption.
With respect to a notebook-style personal computer that is driven by a battery that uses a secondary battery, there is a particularly strong demand to reduce the power consumption, in order to prolong an operating time. In known art, in a state in which the personal computer is driven by the battery, when it is in a state in which the power consumption is lower than that of normal times, such as when it is in a sleep, suspended or hibernation state (hereinafter, these states are also collectively referred to as a “stand-by state”), a power source (this is referred to as an always-on power (ALW power) source in the description below) is turned off, the power source supplying power to portions to which it is considered at least necessary to supply the power, such as an EC (Embedded Controller).
In this way, by appropriately turning off the ALW power when the battery is driven, it is possible to suppress the power consumption when the personal computer is in the sleep or suspended state etc. and to prolong a driving time when the battery is driven.